System of marine propulsion



Feb. 5, 1929.

"r. c. COYK ENDALL SYSTEM OF MARINE PROPULSION Filed Dec. 20, 1924 3Sheets-Sheet l INVENTOR fiamm (L fiZL-A Q ATTORNEYS.

Feb. 5, 1929. 1,701,403

,'r c. COYKENDALL v SYSTEM 01 MARINE 91101 11115101:

Filed Dec. 20, 1924 3 Sheets-Sheet 2 Z?! 43 Zy 4 I I fl cgziw kATTORNEY;

Feb. 5, 1929. v 7 1,701,403

' T. c. COYKENDALL SYSTEM OF MARINE. PROPULSION Filed Dec. 20; 1924 sSheets-Sheet 5 ATTORNEY Patented F ch. 5, 1929.

UNITED STATES PATENT OFFICE.

rrnoms'c. COYKENDALL, or xme'sron, NEW Yonx.

SYSTEM or manure rnororsron;

Application v filed December 20, 1924. Serial K047573227.

This invention relates to systems o'fmarine propulsion and has forits'object the provision of certain improvements in marine -pro-'combustion engines, steam or other elastic fluid turbines, andlike'ships engines, 1s ordin'arily higher than theefficient andeconomical speed ofrotation of the ships propeller. It is thereforecustomary to connect the propeller to'the ships engine throughappropriate speed-reducingagencies, such as reduction gearing.Satisfactory speed-reducing gearing has been developed for this purpose,but it has been found necessary in such gearing, both to avoidobjectionable noise and 'topractically connect the relatively high speedand high power engine to the propeller, to maintain the gearspermanently engaged or meshed. On this account, the

provision of suitable means for obtaining astern-motion of the ship haspresented a.

problem that has been given considerable attention by marine engineers.has heretofore beenthe usual practice to re verse the ships engine or toprovide an auxiliary reversing engine for -astern-motion. Reversing aships engine ,is awkward and slow, particularly in cases of emergency,and the provision of an auxiliary reversing engine is costly andrequires additional space.

The present invention aims to rovide an eflicient and sim le system ofmarine propulsion in which ahead-motion and astern-motion aresatisfactorily effected without reversing the ships engine and withoutproviding an auxiliary reversing engine. Thus,

the improved system of the invention includes a speed-reducing gearingin which the gears thereof are permanently engaged ,or meshed, incombination [with means for I operatively connecting such gearingbetween the .engine and the propeller so as to obtain ahead-motion andastern-motion. This result I am .able to secure by the provision of twopower clutches, preferably ofthc fluid pressure operated friction disktype, one of which clutches when actuated operates to connect theengine'to the propeller through the In, general, it

gearing for ahead-motion while the other clutch when actuated operatesto connect the engine to the propeller through the gearing forastern-motion.

One embodiment of theinvention includes a two-part main shaft (sayconnected to the engine) with a power clutch 'operatively associatedtherewith to connect or disengage the two parts of the shaft, anda-two-part aux llary shaft having a similar clutch operatrvelyassociated therewith. These shafts have one part thereof directly andperma nently connected together by gearing whereby the shafts rotate inopposite directions, and the other parts of these shafts are con nectedto a third shaft (sa the propeller shaft.) through similar spee-reduc1ng 'gear-' ing."- The clutches are preferably of the fluidpressure operated friction disk type, and the system then furtherincludes fluid pressure control means for (1) actuating one of theclutches and simultaneously disengaging the other clutch to effectahead-motion and for (2) actuating the latter clutch and simul-.taneously disengaging the other clutch to effect astern-motion and for(3) simultaneously d1sengaging. both of the clutches. I

. It is frequent y, necessary in systems of marine propulsion to mountthe shipsengine so that its shaft is at a higher level than thepropeller shaft, for the reason. that if the engine shaft is at a lowerlevel than (or the same level as) the propeller shaft there 18 notsufficient room between the center of the engine shaft and the keelsonof the shipfor the bedplate of the engine. The improved system of theinvention 1s admirably adapted to attain this end. Accordingly,;in oneembodiment of the system of the invention the engine or main drivingshaft is arranged at a higher level'than the propeller shaft. I havesecured very excellent results withthe engine and propeller shafts insubstantlally the same vertical plane, the engine shaft belng at ahigher level than the propeller shaft. With'such an arrangement theauxiliary and propeller shafts mayadvantageously be arranged insubstantially-the same horizontal plane. The improved marine propulsionsystem of the invention 'is simply operated and controlled by anappropriate control means for the two power clutches and the usual speedcontrolling means for the ships engine. If

desired, the control means for the clutches may be operativelyassociated and combined with the speed controlling means for theshipsengine so that the manipulation of a single controller efi'ectsahead-motion and astern-motion as well as variations in engine speed asdesired in navigating and maneuvering the shi The novel eatures which Ibelieve to be gatentably characteristic of my invention are efinitelypointed out in the claims appended hereto. The arrangement of theapparatus in and the mode of operation of the system of the invention,in what I now regard as the preferred embodiments thereof, will be bestunderstood from the following description taken in conjunction with theaccompanying drawings, in which Fig. 1 is a diagrammatic plan partly insection of the system,

Fig.2 is aside elevation of the system,

Fig. 3 is an end elevation of the system,

Fig. 4-is an enlarged cross-section of the power clutch employed inthesystem,

Fig. 5 is a detail view of a modified controlling means, and

Fig. 6 is a diagrammatic plan partly in section-of a modifiedarrangement of the system.

Throughout this spec fication and the appended claims I have used theterm engine to ,define any suitable power source for a shi The system ofthe invention is espe- :ia y applicable-for use in conjunction withinternal combustion engines, more part-ion larly-Dlesel engines, steamor other elasticfluid' turbines, and like relatively high speed and highpower engines. By high power, I

mean exceeding 100 horse power and usually several hundred horse power.

Referring now to Figs. 1. 2' and 3 of the accom anying drawings, thereis diagrammatically illustrated a ships engine 6, such, for example, asa Diesel engine. The engine shaft is operatively connected through aforward flexible coupling 7 to a main driving shaft 8-8. The drivingshaft comprises two arts Sand 8 rotatably mounted in suitable arings ingear casings 9 and 10, respectively.

The two parts 8 and 8 of the driving shaft are arranged to. beoperatively connected together or disengaged by a power clutch 11. Theclutch illustrated in the drawings is of the fluid pressure operatedfriction disk type, such, for example, as a Metten oil clutch. Thisclutch (see Fig.4) comprises a disk 12 secured to that part (8) of thedriving shaft which is connected to the engine. The disk has; an annularperipheral portion '12 preferably covered or lined with frictionmaterial, arranged between two relatively movable annular frictionmembers 13 and 14. The annular friction member- 13 is mounted on theinner'face of the annular flange 15 of the clutch casing 15, the casingitself being sememes cured to the part 8' of the driving shaft. The Iannular friction member 14: is mounted on the face of the annular flange16' of a convex- .concave circular plate 16. The plate 16 is secured tothe casing 15-by an annular expansible or bellows metal element 17. Theconcave face of the plate 16 is in' juxtaposition with, but slightlysaced from, the inner convex face of the cas1ng15, and these faces inconjunction with the expansible element 17- form a chamber19 adapted tobe filled with oil supplied through the central hole 18 in the shaft 8.4

The operation of the clutch is as follows: so long as the oil in thechamber 19 is under no pressure, the; normal resiliency of theexpansible element 17 withholds the frictionmember 14 from engagementwith the disk 12. The disk thus rotates" freely in the s ace betweenthefriction members13 and 14. he two parts Sand 8' ofthe driving shaft areaccordingly operatively disengaged and free to rotate independently ofone another. When the oil in the chamber-19 is placed under pressure,through means hereinafter more fully described, "the friction member His forced towards the friction member 13 with the result that the disk12. is securely gripped between these members and thetwo parts 8 and 8'of the driving shaft are operatively connected to rotate asa unitaryshaft.

An auxiliary two-part shaft 20-20 is rotatably mounted in suitablebearings in the gear casings 9. and 10. The two parts 20 and 20 of thisshaft are arranged to be operatively connected together or disengaged bya power clutch 21, of the same construction as the clutch 11. v

The main shaft (part 8) has secured thereto a gear 22 that permanentlyengages or meshes with a similar gear 23 secured to the auxiliary shaft(part/20).. The shaft parts 8 and 20 thus always rotate in oppositedirections. The cars 22 and 23 are preferably of the herringone type toreduce the noise of operation to a minimum. These gears are onc osed ina gear casing diagrammatically represented. in the drawin s by 9. It isto be un- 'on the (propeller shaft. A similar pinion 29 is secure to thepart 20. of the auxiliary shaft and permanently engages or meshes withthe propeller shaft gear 27. In the drawings, a pair of gears 27, andpairs of pinions 28 Inn - The auxiliary shaft 20' extreme left-handpositions,

and 29 are illustrated, but it will be understood that each'ofthesepairs functions as a single unit, the duplication being made formechanical reasons.

The gears and pinions 27, 28 and 29 are of the herring-bone type and areenclosed in the ear casing 10 which is like the gear casing 9.

The main shaft 8-8 is at a higher level than the propeller shaft 26, andthe two shafts are in substantially the same vertical plane (see Fig.3), although the shafts are longitudinally somewhat displaced, that isnot directly one above the other except for. a short portion of theadjacent ends thereof.

and the propeller shaft 26 are in substantially the same horizontalplane (see Fig. 3) and similarly longitudinally somewhat displaced thatis, not directly side by side except for a short portion of the adjacentends thereof. Thus, the pinion 28 mesheswith the top portion of thepropeller shaft gear 27 and the pinion 29 meshes with one side (90angular degrees removed from the point of engagement of pinion 28) ofthe gear 27.

In the arrangement illustrated in the drawings the shaft 88 is theahead-motion shaft and the shaft 20-20 is the reverse or asternmotionshaft. These two shafts are driven by the engine at the same speeds butin opposite directions. The desired speed reduction is secured as aresult of the pinions 28 and 29 meshing with the gear 27.

The clutches 11 and 21 are controlled by a clutch control valve 30. Thisvalve has a central port communicating by a pipe 31 with a high pressureoil tank 32. The pressure of the oil in the tank 32 is established andmaintained by an oil pump 33 connecting the tank 32 with a lowpressureoil tank or sump 34. P

The valve has a port at each end thereof communicating by a pipe 35 withthe sump 34. Between the-central port and each end port, the valve 30has intermediate ports communicating by pipes 36 and 37 and the centralholes in shaft parts 8 and 20' with the oil chambers 19 of the clutches11 and 21, respectively.

The valve 30 has a movable piston 38 connected by appropriate linkage 39to a control lever or handle 40. \Vhen the piston 38 and the lever 40are in their extreme right-hand positions, as shown in the drawings. theoil pipe 36 is in communication with the high pressure oil tank 32 andclutch 11 is actuated and operatively connects together the two shaftparts 8 and 8'. At the same time the oil pipe 37 is in communicationwith the oil sump 34 and the clutch 21 is accordingly disengaged,thereby permitting independent rotation of the two shaft parts 20 and20. hen the piston 38 and control lever 40 occupy their as viewed in thedrawings, the clutch 21 is actuated and the clutch 11 is disengaged.\Vhen the piston 38 ing in the direction indicated by the two clutches11 and 21 will be propeller,

the same time.

The operation of the system illustrated in the drawings is as follows.By changing the position of lever 40 from its neutral position to itsahead or astern position, the direction of the flow of oil (underpressure from tank 32) is changed in pipes 36 and 37 so that thepropeller 24 is caused to rotate in either a right-hand or left-handdirection, causing the ship or boat to move ahead (forward) or astern(backward); \Vith the lever 40 in its neutral position and oil pipes36'and 37 in communication with the sump. 34, and engine 6 runningcounter-clockwise looking from the propeller, the gears 22 and 23 willbe rotatthe arrows in Fig. 1, disengaged and the propeller will remainstationary. When the lever 40 is moved to its ahead position, the clutch11 is actuated and clutch 21 disengaged, whereby power is transmittedfrom the engine 6 through the clutch 11 to the pinion 28 to thepropeller shaft gear 27, causing the propeller to rotate in a clockwisedirection, and the boat to move ahead (forward).

To reverse the direction of rotation of the the lever 40 is moved to itsastern osltion. The clutch 21' is thereby actuated and the clutch 11disengaged, whereupon power is transmitted from the engine 6 throughgears 22 and 23, clutch 21 and pinion 29 to the propeller shaft gear 27,causing the propeller to rotate in a counter-clockwise direction and theboat to move astern (backward).

In Fig. 5 of the drawings, I have diagrammatically illustrated anarrangement for effecting control of the direction of rotation ofthepropeller and the speed of the ships engine by a single means, whichmay be 10-- eated in the pilot house or in the engineroom, or whereverconvenient.

lower 41 actuates in any appropriate manner the throttle or other speedcontrolling device of the ships engine. Appropriate movement of the camfollower 41 for effecting the desired speed control of the engine isobtained by a cam 42 secured to the lever 40 to turn with the leverabout its pivot point. Movement of the lever 40 through the angles a and6 effects the actuation of the headniotion'clutch or the astern-motionclutch, as the case may be. But this movement of the A cam follever doesnot alter the position of the cam follower 41 and the ships enfgineoperates at its minimum speed, say 100 P. M. Movement of the leverthrough the angle 0 or (1 causes the cam follower 41 to move outward"angle 0, the ahead-motion clutch remains energized and the astern-motionclutch re-' mains disengaged, and similarly during the movement of thelever 40 through the angle 03 the astern-motion clutch remains energizedand the ahead-motion clutch remains disengaged. 1 v

The marine propulsion system of the invention is of simple and ruggedconstruction, easily and readily controlled and eflicient in operation.The desired speed reduction between a single engine, running always inthe same direction and the propeller is secured by an arrangement ofpermanently engaged gearing, relatively noiseless in operation. Thesystem is of particular advantage in ships which in service must becontinually maneuvered, such, for example, as

tug-boats. The gearing and power clutches can be designed andconstructed for the transmission of very high powers from engine topropeller, and the system of the in vention is therefore applicable toequipments in which the power source is of several hundred horse powerand higher.

The arrangement of apparatus illustrated in Figs. 1, 2 and 3 of theaccompanying drawings 1s of particular advantage where it is necessaryto mount the engine shaft at a higher level than the propeller shaft. Itis also of advantage in ships having a single propeller. In ships havingtwin propellers, the modified arrangement illustrated in Fig. 6 hascertain advantages, since it permits convenient mounting of the twoships engines (one for each propeller) near the center of the shiptogether with pr'operarrangement of the reducing gearing and the twopropeller shafts.

Referring now to Fig. '6 of the drawings, similar parts have beenrepresented by the same reference character as in Figs. 1, 2 and 3. Thearrangement illustrated is for a ship with twin propellers and it is tobe understood that the apparatus shown is for the port propeller onl theapparatus for the staroard propel er being identical therewith.

The engine 6 is connected by a flexible coupling 7' to a shaft 43rotatably mounted in the gear casing 10". A pinion 44 is secured to theshaft 43 and permanently engages or meshes with gears and 46'positionedon opposite sides thereof. The gears 45 and 46 are secured to the parts47 and 48 of two-part main; and auxiliary shafts 47-474 and 48-48respectively. The main and auxiliary shafts are appropriately mountedfor rotation in the gear casings 9 and 10. The three shafts 43, 47-47and 48-48 are arranged in substantially the same horizontal plane.

The propeller 24 is secured to the main shaft part 47. Permanentlyengaged gears 49 and are secured to the main shaft part 47' and theauxiliary shaft part 48 respectively. The pinion 44 and gears 45, 46, 49and 50 are preferably of the herring-bone type. Power clutches 11 and21' are operatively associated with the shafts 47-47 and 48-48,respectively. These power clutches are of the fluid pressure operatedfriction disk type illustrated in Fig. 4 of the drawings, and arecontrolled by instrumentalities of substantially the same constructionas illustrated in Fig. 1 for the control of the clutches 11 and 21. p

The operation of the system of Fig. 6 is substantially as follows. Forahead-motion, the power clutch 11 is actuated and energized and thepower clutch 21' is disen aged. Power is transmitted from the engine 6to the propeller 24 through the pinion 44, gear 45 and main shaft 47-47.The gears in the system will rotate in the directions indicated by thefull-line arrows and the propeller will be rotated to move the shipforward or ahead. For reversing or astern-motion, clutch 21 is actuatedand energizedand the power clutch 11 disengaged. Power is thereupontransmitted from the engine 6' to the propeller 24 through thepinion 44,gear 46, auxiliary shaft 48-48 and gears 50-49. The pinion 44 andgearing46 will rotate in the same direction as for ahead-motion, but thegears 49 and 50 will rotate in the opposite direction, as indicated by.the dotted line arrows. The propeller will accordingly rotate in adirection to move the ship astern or backward.

vI. claim:

1. A system of marine propulsion, comprising a propeller, an internalcombustion engine, a two-part ahead-motion shaft, a power clutch of thefluid pressure operated friction type adapted to slip under excessiveload and arranged to either operatively connect or dis engage the twoparts of said ahead-motion shaft, a two-part astern-motion shaft, apower clutch of the fluid pressure operated friction type adapted toslip under'excessive load and arranged .to either operatively connect ordisengage the two parts of said astern-motion shaft, permanently engagedgearing for operatively connecting said engine to said propeller throughsaid ahead-motion shaft to effect ahead propulsion when the clutch'inthat shaft is energized and the other clutch disengaged and foroperatively connecting said engine to said propeller through saidasternmotion shaft to effect astern propulsion when the power the clutchin the latter shaft is energized and the other clutch disengaged, "andcontrol means for energizing at will one or the other of said clutches.t

- 2. A systemof marine propulsion comprising a propellershaft,aninternal combustion engine, a gear secured to said propeller shaft, atwo-part main driving shaft having one part thereof directly connectedto said engine, a power clutch of the fluid pressure 0perated frictiontype adapted to slip under excessive load and arranged to eitheroperatively connect or disengage the two parts of said main drivingshaft, a gear secured to that part of said main driving shaft betweensaid clutch and said engine, a pinion secured to the other part of saidmain driving shaft meshing with the gear on said propeller shaft, atwo-part auxiliary driving shaft, a power clutch of the fluid pressureoperated friction type adaptedto slip under excessive load and arrangedto either operatively connect or disengage the two parts of saidauxiliary driving shaft, a gear secured to one part of said auxiliarydriving shaft meshing with the gear on said main driving shaft, a pinionsecured to the other part of said auxiliary driving shaft meshing withthe gear on said propeller shaft, and control means for energizing atwill one or the other of said clutches.

3. A system of marine propulsion, comprising a propeller shaft, anengine, a two-part ahead-motion shaft, a two-part astern-motion shaft, apower clutch of the fluid pressure operated friction type adapted toslip under excessive load and operatively associated with each of saidahead-motion and astern-motion shafts and arranged to either operativelyconnect or disengage the two parts of the shaft, permanently engagedgearing for operatively connecting said engine to said propeller shaftthrough said ahead-motion shaft to effect ahead propulsion when theclutch in that shaft is energized and the other clutch disengaged andfor operatively connectin said-engine to said propeller shaft througsaid astern-motion shaft to effect astern propulsion when the clutch in.the latter shaft is energized and the other clutch disengaged, andcontrol means for energizing at will one or the other of said clutches.

4. A system of marine propulsion, comprising a propeller shaft, anengine, a two-part ahead-motion shaft having one part thereof directlyconnected to the shaft of said engine, a two-part astern-motion shaft, apower clutch operatively associated with each of said ahead-motion andastern-motion shafts and arranged to either connect or disengage the twoparts of the shaft, permanently'engaged gearing for operativelyconnecting said engine to said propeller shaft through said ahead-motionshaft to effect ahead propulsion and through said astern-motion shaft toeffect astern propulsion, and control means for energizing at will oneor'the other of said clutches.

5. A system of marine propulsion, comprising a propeller, an engine, atwo-part ahead motion shaft, a two-part astern-motion shaft, a powerclutch operatively associated with each of said shafts and arranged toeitherconnect or disengage the two parts of the shaft, said ahead-motionshaft being mounted at a higher level than said astern-motion shaft,permanently engaged gearing for operatively connecting said engine tosaid propeller through said ahead-motion shaft to effect aheadpropulsion when the clutch in that shaft is actuated and the'otherclutch disengaged and for operatively connecting said engine to saidpropeller through said asternmotion shaft to effect astern propulsionwhen the clutch in the latter shaft is actuated and the other clutchdisengaged, and control means for actuating one or the other of saidclutches or simultaneously disengaging both of said clutches as desired.

6. A system of marine propulsion, comprising a propeller shaft, anengine, a two-part ahead-motion shaft,a two-part astern motion shaft, apower clutch operatively associated with each of said ahead-motion andastern-motion shafts and arranged to either connect or disengage the twoparts of the shaft, the axes of said propeller and asternmotion shaftsbeing in substantially the same horizontal plane and saidahead-motion-shaft being mounted at a higher level than said propellerand astern-motion shafts, permanently engaged gearing for operativelyconnecting said engine to said propeller shaft through said ahead-motionshaft to effect ahead ropulsion and through said astern-motion s aft toeffect astern propulsion, and control means for (1) actuating the clutchassociated with said ahead-motion shaft and simultaneously disengagingthe other clutch and for (2-) actuating the clutch associated with saidastern-motion shaft and simultaneously disengaging the other clutch andfor (3) simultaneously disengaging both of said clutches as desired.

7. A system of marine propulsion, comprising a propeller shaft, anengine, a two-part ahead-motion shaft operatively connected to saidengine, a two-part astern-motion shaft, a clutch operativelyassociatedwith each of said ahead-motion and astern-motion shafts andarranged to either connect or disengage the two parts of the shaft, theaxes of said propeller and astern-motion shafts being in substantiallythe same horizontal plane and the axes of said propeller andahead-motion shafts being in substantially the same vertical plane withthe ahead-motion shaft at a higher level than the propeller shaft,permanently engaged gearing for operatively connecting said engine tosaid propeller shaft through said ahead-motion shaft to effect aheadpro- 130 said ahead-motion shaft and simultaneously disengaging theother clutch and for (2) actuating the clutch associated with saidasternmotion shaft and simultaneously disengaging the other clutch andfor (3) simultaneously disengaging both of said clutches as desired.

8. A system of marine propulsion, coniprising a propeller shaft, anengine, a twopart ahead-motion shaft having one part thereof directlyconnected to the shaft of said engine, a two-part astern-motion shaft, a

clutch operatively associated with each of said ahead-motion andastern-motion shafts and arranged to either connect or disengage the twoparts of the shaft, said engine shaft being mounted at a higher levelthan said proller shaft, permanently engaged gearing or operativelyconnecting said engine to said propeller shaft through said ahead-motionshaft to effect ahead propulsion and through said astern-motion shaft toeffect astern propulsion, and control means for (1) actuating the clutchassociated with said ahead-motion shaft and simultaneously disengagingthe other clutch and for (2) actuating the clutch associated with saidastern-motion shaft and simultaneously disengaging the other clutch andfor (3) simultaneously disengaging both of said clutches as desired.

9. A system of marine propulsion, comprising a propeller shaft, anengine, a twopart ahead-motion shaft having one part thereof directlyconnected to the shaft of said engine, a power clutch of the fluidpressure operated friction type adapted to slip under excessive load andarranged to either operatively connect or disengage the two parts ofsaid ahead-motion shaft, a two-part astern-motion shaft, a power clutchof the fluid pressure operated friction type adapted to slip underexcessive load and arranged to either operatively connect or disengagethe two parts of said astern-motion shaft, permanently engaged gearingfor operatively connecting said engine to said propeller shaft throughsaid ahead-motion shaft to effect ahead propulsion when the clutch inthat shaft is energized and the other clutch disengaged, and foroperatively connecting said engine to said propeller shaft through saidastern-motion shaft to effect astern propulsion when the clutch in thelatter shaft is energized and the other clutch disengaged, and controlmeans for energizing at will one or'the other of said clutches.

10. A system of marine propulsion, comprising a propeller shaft, apropeller operatively connected to said shaft, a gear secured to saidpropeller shaft, an engine, a two-part driving shaft operativelyconnected to said engine, a power clutch of the fluid pressure operatedfriction disk type operatively associated with said shaft and arrangedto either connect or disengagethe two parts thereof, a gear on that partof said driving shaft between said clutch and said engine, a pinion onthe other part of said driving shaft meshing with the gear on saidpropeller shaft, a two-part auxiliary shaft, a power clutch of the fluidpressure operated friction disk type operatively associated with saidauxiliary shaft and arranged to.

either connect or disengage the two parts thereof, a gear on one part ofsaid auxiliary shaft meshing with the gear on said driving shaft aPlIllOIl on the other part 'of said auxil ary shaft meshing with thegear on said propeller shaft, and means for engaging one or the other ofsaid clutches or simultaneousl disengaging both of said clutches asdesired.

11. A system of marine propulsion, comprising a propeller shaft, apropeller operatively connected to said shaft, a gear secured to saidpropeller shaft, an engine, a two-part driving shaft operativelyconnected to said engine, a clutch arranged to operatively connect ordisengage the two parts of said driving shaft, a gear on that part ofsaid driving shaft between said clutch and said engine, a pinion on theother part of said driving shaft meshing with the gear on said propellershaft, a two-part auxiliary shaft, a clutch arranged to operativelyconnect or disengage the two parts of said auxiliary shaft, a gear onone partof said auxiliaryshaftmeshing with the gear on said drivingshaft, a pinion on the other part of said auxiliary shaft meshing withthe gear on said propeller shaft, said driving shaft being mounted at ahigher level than said propeller shaft, and means I for engaging one orthe other of said clutches or simultaneously disengaging both of saidclutches asdesired.

12. A system of marine propulsion, comprising a propeller shaft, apropeller operatively connected to said shaft, a gear secured to saidpropeller shaft, an engine, a twopart driving shaft operativelyconnected to said engine, an ahead-motion power clutch arranged toeither operatively connect or disengage the two parts of said drivingshaft, a gear secured to that part of said driving shaft between saidclutch and said engine, a pinion secured to the other partof saiddriving shaft meshing with the gear on said propeller shaft, a two-partreversing-shaft, the axes of said propeller and reversing shafts beingin substantially the same horizontal plane and the axes of saidpropeller and driving shafts being in substantially the same verticalplane with the driving shaft at a higher level than the propeller shaft,an asternmotion power clutch arranged to either operatively connect ordisengage the two-parts of said reversing shaft, a gear secured to onepart of said reversing shaft meshing with the gear on said drivin shaft,apinion seating said ,astern-motion clutch and simulcured to the otherpart 0%said reversing shaft taneously disengaging said ahead-motionmeshing with the gear on said propeller clutch to efi'ect asternpropulsion and for (3) 10 shaft, and control means for (1) actuatingsimultaneous1y disengaging both of said 5 said ahead-motion clutch andsimultanel hes as deslre'd.

ously disengaging said astern-motion clutch In testimony whereof I aflixmy signature to effect ahead propulsion and for (2) actu- THOMAS C.COYKENDALL.

